Three weeks before Election Day, election officials in a suburban Atlanta county have rejected hundreds of absentee ballots, prompting state and local inquiries and legal challenges by voting rights advocates, who say the moves have disproportionately affected African American, Latino and Asian American voters.

Among the reasons cited for ballots being tossed are signatures that do not match those on file, missing addresses and incorrect birth years, according to state data.

The data show that more than 1,200 ballots have been rejected statewide. The number of rejected ballots is most concentrated in Gwinnett County, northeast of Atlanta, where 465 ballots had been tossed as of Monday night — 38 percent of all those rejected statewide.

“This is an unprecedented number of disqualifications, and it’s happening in a county where there are a number of contested races that have minority candidates on the ballot,” said Andrea Young, executive director of the Georgia chapter of the American Civil Liberties Union, which filed a lawsuit Tuesday against state and local election officials over the rejected ballots.

“This is cumulative,” she added. “It’s not an isolated instance.”

Gwinnett County, the state’s second-largest county, has undergone a demographic transformation in recent years, moving from 67 percent white in 2000 to 62 percent nonwhite last year. Democrats have sought to mobilize the new residents in support of their efforts to turn the state blue.

Voters cast ballots at the Municipal Building in Augusta, Ga., on Monday morning, the day early voting began. (Michael Holahan/AP)

It’s unclear why Gwinnett County is rejecting more absentee ballots than other counties in Georgia, but some voting rights advocates said a new law that changed the information voters must provide on the envelope used to send in the ballots may have caused confusion.

Gwinnett County spokesman Joe Sorenson said in a statement Tuesday evening that the county “is committed to a process that protects the voting rights of all of its citizens and fully complies with the law in the process.”

“The handling of absentee ballot applications and the acceptance and rejection of ballots by Gwinnett County has complied with the law and will continue to do so,” he said, adding that there have been no allegations that county officials are violating the law.

Stephen Day, the chairman of the county elections board, told the Atlanta Journal-Constitution that an examination of the matter was underway. Day, a Democrat, rejected the possibility of intentional voter suppression.

A spokeswoman for Georgia Secretary of State Brian Kemp said his office is also looking into the ballot rejections. Kemp, the Republican nominee for governor, is locked in a fierce debate about voting access with his opponent, Democrat Stacey Abrams, who has accused him of supporting efforts to disenfranchise voters of color.

“We will not be bullied by out-of-state organizations or political operatives who want to generate headlines and advance a baseless narrative,” said Kemp’s spokeswoman, Candice Broce. “We will do our part to keep elections secure, accessible, and fair in Georgia.”

The revelations about the absentee ballot rejections come days after the Associated Press reported that election officials across Georgia had suspended more than 50,000 applications to register to vote, most of them for black voters, under a rigorous Republican-backed law that requires personal information to exactly match driver’s license or Social Security records.

Nearly 2.5 million Georgians cast ballots in the 2014 gubernatorial election, when Republican Gov. Nathan Deal beat his opponent by more than 200,000 votes. This year’s contest appears to be much closer.

Republican lawmakers in Georgia have passed legislation in recent years that they say is intended to curtail voter fraud but that critics say restricts ballot access — particularly for voters of color, students and people with lower incomes, who tend to vote Democratic.

The state is home to one of the country’s most restrictive voter ID laws. Changes to the mail-in ballot envelope were part of a broader law passed in 2017 requiring voters’ registration applications to exactly match their driver’s license and Social Security records.

Kemp has championed these policies. His office implemented the “exact match” policy long before the law was passed, but the effort was curtailed by a settlement agreement reached during litigation.

“Georgia is ground zero in the battle for protecting voting rights and voter suppression,” said John Powers, a lawyer with the Lawyers’ Committee for Civil Rights Under Law, which sent a letter late Monday to state and local election officials asking that they make sure voters are quickly informed about their rejected ballots to give them time to fix any errors and cast ballots.